The present invention concerns a fluid-actuated locking device controlled by a combination for the doors of dwelling and offices and for armored doors.
It is well known that safety devices used until now for the doors of dwellings and offices comprise somewhat complicated mechanically operated combination locks (using letters or numbers). Also the safety devices for safes usually work mechanically, and the opening or locking of their doors is effected by means of a key.
Apart from the usual somewhat complicated locks, mechanically operated combination locks show many disadvantages. First of all, space is needed to install the entire device. Another disadvantage lies in the fact that the position of the locking zones of the door depends on the geometry of the device, and further, each locking zone needs separate operating means. Moreover, all the mechanical elements are subject to wear. Not least, with such mechanically operated devices it is possible for a thief to figure out the combination by probing for unavoidable noises, even if these are barely audible. Furthermore, in such devices the locking zones are all mechanically interconnected. If the thief gets control of one of these locking zones, he will control the others and thus the entire device. Finally, with regard to the locking and the opening of the door, a key is needed. Moreover, these disadvantages are associated with high investment costs.
It is therefore the aim of the present invention to provide a combination-controlled safety device for the doors of dwellings and offices which needs very little space for its installation in a door, is subject to a very low wear rate, is simple and economical, and whose operation is absolutely noiseless so that no information can be derived about the predetermined combination through probing for noises, and wherein the individual locking zones of the door are not dependent on geometrical factors and can therefore be installed in any area of the door, and wherein no key is needed for the opening and locking of said door.